Abstract:

A method for manufacturing a display device is disclosed, which includes
forming a main sealant which surrounds a display region on a first
substrate and an auxiliary sealant which is disposed along and outside
the main sealant and has an epoxy resin and a diazonaphthoquinone type
initiator, disposing a second substrate on the first substrate and
aligning the first and second substrates, and adhering the first and
second substrates by curing the auxiliary sealant with UV radiation.

Claims:

1. A method for manufacturing a display device, comprising:forming a main
sealant which surrounds a display region on a first substrate and an
auxiliary sealant which is disposed along and outside the main sealant,
where the auxiliary sealant comprises an epoxy resin and a
diazonaphthoquinone initiator;disposing a second substrate on the first
substrate and aligning the first and second substrates; andadhering the
first and second substrates by curing the auxiliary sealant with UV
radiation.

2. The method of claim 1, wherein the epoxy resin comprises at least two
epoxy groups.

8. The method of claim 7, wherein the novolac resin of the
diazonaphthoquinone initiator comprises a phenol novolac resin, and a
number-average molecular weight Mn of the phenol novolac resin is from
about 1,000 to about 50,000 g/mol.

9. The method of claim 1, wherein the auxiliary sealant further comprises
a hardener.

10. The method of claim 9, wherein a molar ratio of hardener to epoxy
resin is about 1:5 to about 1:20.

11. The method of claim 9, wherein the hardener comprises a dihydrazide
material.

12. The method of claim 11, wherein the dihydrazide material comprises at
least one selected from the group consisting of valine dihydrazide,
adipic acid dihydrazide and sebacic acid dihydrazide.

13. The method of claim 1, further comprising curing the main sealant by
heating after the auxiliary sealant is cured,wherein a glass transition
temperature of the cured auxiliary sealant is higher than a curing
temperature of the main sealant.

14. The method of claim 13, wherein the main sealant is cured by heating
at about 100.degree. C. to about 140.degree. C.

15. The method of claim 13, further comprising:forming a substrate
assembly having the main sealant disposed between the first and second
substrates by cutting along a cutting line outside of the main sealant;
andinjecting liquid crystals between the first and second substrates
through an injection opening formed in the main sealant,wherein the
auxiliary sealant is disposed outside of the cutting line.

16. The method of claim 15, wherein the liquid crystals comprise a liquid
crystal having a twisted nematic (TN) mode.

17. A composition of a sealant comprising diazonaphthoquinone-novolac
resin and a novolac epoxy resin present in a molar ratio of about 1:10 to
about 1:100.

18. The composition of claim 17, wherein the novolac resin of the
diazonaphthoquinone-novolac resin comprises a phenol novolac resin having
a number-average molecular weight Mn of from about 1,000 to about 50,000
g/mol.

19. The composition of claim 17, further comprising a hardener comprising
a dihydrazide material.

Description:

[0001]This application claims priority to Korean Patent Application No.
10-2007-0085697, filed on Aug. 24, 2007, and all the benefits accruing
therefrom under 35 U.S.C. 119(a), the content of which is incorporated
herein by reference in its entirety.

BACKGROUND OF THE INVENTION

[0002]1. Field of the Invention

[0003]The present invention relate to a method for manufacturing a display
device and a composition of a sealant therefor.

[0006]Typically, an LCD can include a first substrate having thin film
transistors, a second substrate coplanar with and facing the first
substrate, and a liquid crystal layer interposed between the first and
second substrates. The first and second substrates are adhered to one
another with a sealant.

[0007]Patterns including signal lines, pixel electrodes, a black matrix
and color filters are formed in the first and second substrates in the
LCD. Aligning the first and second substrates precisely is critical to
providing improved display quality.

[0008]However, the first and second substrates can become misaligned
during the manufacturing process. Imprecise alignment thereby reduces the
display quality.

BRIEF SUMMARY OF THE INVENTION

[0009]Additional aspects and/or advantages of the present invention will
be set forth in part in the description which follows and, in part, will
be obvious from the description, or may be learned by practice of the
present invention.

[0010]The foregoing and/or other aspects of the present invention are also
achieved by providing, in an embodiment, a method of making a display
device, including: forming a main sealant to surround a display region on
a first substrate, and an auxiliary sealant which is disposed in a
circumference of the main sealant and has an epoxy resin and a
diazonaphthoquinone type initiator; disposing a second substrate on the
first substrate and aligning the first and second substrates; and
adhering the first and second substrates by curing the auxiliary sealant
with UV.

[0011]The epoxy resin can include at least two epoxy groups.

[0012]The epoxy resin can include a novolac type epoxy resin.

[0013]The novolac type epoxy resin can include at least one of a phenol
novolac epoxy resin and a cresol novolac epoxy resin.

[0014]The epoxy resin can have a chemical structure of chemical formula 1.

##STR00001##

[0015]Here, R' includes at least one selected from the group consisting of
amide, ester, ether, sulfide, sulfoxide, hydroxide, halide, imide, an aza
group, amine, an azo group, aldehyde, a carboxy group, anhydride, urea,
an alkyl group, and an alkylaryl.

[0016]The molar ratio between the diazonaphthoquinone type initiator and
the epoxy resin can be 1:10 to 1:100, respectively.

[0017]The diazonaphthoquinone type initiator can include a
diazonaphthoquinone-novolac resin.

[0018]The novolac resin of the diazonaphthoquinone type initiator can
include a phenol novolac resin, and the number-average molecular weight
(Mn) of the phenol novolac resin is from 1,000 to 50,000 g/mol.

[0019]The auxiliary sealant can further include a hardener.

[0020]The molar ratio between the hardener and the epoxy resin can be 1:5
to 1:20, respectively.

[0021]The hardener can include a dihydrazide material.

[0022]The dihydrazide material can include at least one selected from the
group consisting of valine dihydrazide, adipic acid dihydrazide and
sebacic acid dihydrazide.

[0023]The method of making can further include curing the main sealant by
using heat after the auxiliary sealant is cured, wherein the glass
transition temperature of the cured auxiliary sealant is higher than the
curing temperature of the main sealant.

[0024]The main sealant can be cured by heating at about 100° C. to
about 140° C.

[0025]The method of making can further include: forming a mother substrate
assembly by cutting the first and second substrates having the main
sealant along a cutting line outside of the main sealant; and injecting
liquid crystals between the first and second substrates through an
injection opening formed in the main sealant, wherein the auxiliary
sealant is disposed outside of the cutting line.

[0026]The liquid crystals can include liquid crystals having a twisted
nematic ("TN") mode.

[0027]The foregoing and/or other aspects of the present invention can be
achieved by provision of a composition of a sealant which includes
diazonaphthoquinone-novolac resin and a novolac type epoxy resin present
in a molar ratio of 1:10 to 1:100, respectively.

[0028]The novolac resin of the diazonaphthoquinone-novolac resin can
include a phenol novolac resin, wherein the number-average molecular
weight (Mn) of the phenol novolac resin is from 1,000 to 50,000 g/mol.

[0029]The composition of the sealant can further include a hardener which
is a dihydrazide type material.

BRIEF DESCRIPTION OF THE DRAWINGS

[0030]The above and/or other aspects of the present invention will become
apparent and more readily appreciated from the following detailed
description of the invention, taken in conjunction with the accompanying
drawings of which:

[0031]FIG. 1 is an exploded perspective view of a liquid crystal display
according to an exemplary embodiment of the present invention;

[0032]FIG. 2 is a sectional view of the liquid crystal display, taken
along the line II-II in FIG. 1;

[0036]Hereinafter, exemplary embodiments of the present invention will be
described with reference to accompanying drawings, wherein like numerals
refer to like elements and repetitive descriptions will be avoided as
necessary.

[0037]It will be understood in the following disclosure of the present
invention, that as used herein, the singular forms "a", "an" and "the"
are intended to include the plural forms as well, unless the context
clearly indicates otherwise. It will be further understood that the terms
"comprise", "comprises", and "comprising," when used in this
specification, specify the presence of stated features, integers, steps,
operations, elements, components, and combination of the foregoing, but
do not preclude the presence and/or addition of one or more other
features, integers, steps, operations, elements, components, groups, and
combination of the foregoing.

[0038]It will be understood that when an element is referred to as being
"on" another element, or when an element is referred to as being
"disposed between" two or more other elements, it can be in at least
partial contact with the other element(s), or an intervening element or
elements may be present therebetween. In contrast, when an element is
referred to as being "directly on" another element, the elements are
understood to be in at least partial contact with each other, unless
otherwise specified. Spatially relative terms, such as "between", "in
between" and the like, may be used herein for ease of description to
describe one element or feature's relationship to another element(s) or
feature(s) as illustrated in the figures. It will be understood that the
spatially relative terms are intended to encompass different orientations
of the device in use or operation in addition to the orientation depicted
in the figures. The device may be otherwise oriented (rotated 90 degrees,
inverted, or at other orientations) and the spatially relative
descriptors used herein interpreted accordingly. Likewise, use of the
term "opposite", unless otherwise specified, means on the opposing side
or surface of the element. For example, where a surface of a layer is
said to be opposite another surface or element, it is located on the
opposing surface of the layer coplanar with the first surface unless
otherwise specified.

[0039]Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which this invention
belongs. It will be further understood that terms, such as those defined
in commonly used dictionaries, should be interpreted as having a meaning
that is consistent with their meaning in the context of the relevant art
and will not be interpreted in an idealized or overly formal sense unless
expressly so defined herein.

[0040]Hereinafter, a liquid crystal display will be exemplified as a
display device, but should not be considered by this exemplification as
limited thereto. For example, practice of the present invention as
disclosed herein can be applied to other display devices such as an
organic light emitting device or an electrophoretic display device.

[0041]Referring to FIGS. 1 and 2, a liquid crystal display which is made
according to a method of the present invention will be described.

[0042]FIG. 1 is an exploded perspective view of a liquid crystal display
according to an exemplary embodiment of the present invention and FIG. 2
is a sectional view of the liquid crystal display, taken along the line
II-II in FIG. 1.

[0043]As shown in FIG. 1, a liquid crystal display 1 includes a first
substrate 100, a second substrate 200, and sealants 310 and 320 disposed
on a surface of the first substrate 100. For convenience, FIG. 1 does not
illustrate a liquid crystal layer 400 shown in FIG. 2. The sealants 310
and 320 include a main sealant 310 which substantially surrounds a
display region (DISPLAY REGION in FIG. 1) on the surface of first
substrate 100, and a capping sealant 320 which spans the interim distance
between ends of the sealant 310 which does not completely surround the
display region, such that the combination of sealants 310 and 320
completely surround the display region.

[0044]The first substrate 100 is larger than the second substrate 200. The
inside part of the first substrate 100 bounded by sealants 310 and 320
includes the display region while the outside part thereof is a
non-display region (NON-DISPLAY REGION in FIG. 1). The first substrate
100 includes an array of gate lines 121 which extend to the display
region, gate pads 122 which connect with the gate line 121 and are
disposed in the non-display region, an array of data lines 131 which
extend to the display region and data pads 132 which connect with the
data lines 131 and are disposed in the non-display region.

[0045]One gate line 121 and one data line 131 (not shown in FIG. 2) are
connected to one thin film transistor 140 (FIG. 2). The gate line 121
applies a gate signal synthesized with a gate-on voltage and a gate-off
voltage to the thin film transistor 140 while the data line 131 applies a
data voltage to the thin film transistor 140.

[0046]Each of the gate pads 122 receives a gate signal from a gate driver
(not shown), and each of the data pads 122 receives a data voltage from a
data driver (not shown).

[0047]In one exemplary embodiment, the gate pads 122 can be omitted.

[0048]Sealants 310 and 320 adhere the first and second substrates 100 and
200 to each other, and together with the first and second substrates 100
and 200, surround and enclose the liquid crystal layer 400. The sealants
310 and 320 are formed in the non-display region along and outside the
circumference of the display region. The sealants 310 and 320 include an
epoxy resin, and can further include an acrylic resin, an amine type
hardener, and a filler such as alumina powder, or the like.

[0049]Referring to FIG. 2, the liquid crystal display 1 will be described
in more detail.

[0050]The first substrate 100 includes a plurality of thin film
transistors 140 formed on a surface of a first insulating substrate 110.
As described above, thin film transistors 140 are connected to the gate
lines 121 and the data lines 131. The first insulating substrate 110 can
be made of an electrically insulating material such as, for example,
glass, quartz, or plastic.

[0051]An insulating layer 150 is formed on the insulating substrate 110
and over a surface of the thin film transistors 140. A plurality of
contact holes 151 are formed in the insulating substrate 150 to expose
portions of the thin film transistors 140 therethrough.

[0052]A plurality of pixel electrodes 160 are formed on a surface of the
insulating layer 150 opposite the insulating substrate 110. The pixel
electrodes 160 includes a transparent conductive material such as indium
tin oxide ("ITO") and indium zinc oxide ("IZO"). The pixel electrodes 160
are connected to the thin film transistors 140 through the contact holes
151.

[0053]A first alignment layer 170 is formed on a surface of the pixel
electrodes 160 opposite the insulating layer 150. The first alignment
layer 170 may be made of a suitable material such as, for example,
polyimide or silicon oxide.

[0054]The second substrate 200 includes a black matrix 220 formed on a
surface of a second insulating layer 210. The second insulating substrate
210 may be made of an electrically insulating materials such as, for
example, glass, quartz or plastic.

[0056]The black matrix 220 may be formed in a grid pattern. In addition,
the black matrix 220 may be made of a suitable black matrix material. The
black matrix material can include, for example, chromium oxide or an
organic material having a black pigment.

[0057]A plurality of color filters 230a-230c are formed on a surface of
the second insulating substrate 210. The color filters 230a-230c are
disposed portions corresponding to the pixel electrodes 160. The color
filters 230a-230c are formed in a regular pattern, and includes three
distinct sub layers 230a, 23b and 230c which form a repeating pattern and
each of which has a different color, for example, red, green, or blue.

[0058]An overcoat layer 240 is formed on a surface of the color filters
230a-230c and the black matrix 220 opposite the second insulating layer
210. The overcoat layer 240 provides a planar surface and protects the
color filters 230a-230c.

[0059]A common electrode 250 is formed on a surface of the overcoat layer
240 opposite the color filters 230 and the black matrix 220. The common
electrode 250 includes a transparent conductive material such as ITO or
IZO, and applies a voltage across the liquid crystal layer 400 together
with the pixel electrodes 160 to adjust the alignment of the liquid
crystal layer 400.

[0060]A second alignment layer 260 is formed on a surface of the common
electrode 250 opposite the overcoat layer 240. The second alignment layer
260 may be made of a suitable material such as, for example, polyimide or
silicon oxide. The first and second alignment layers 170 and 260 are
aligned perpendicularly to each other (i.e., are aligned when viewed
along the thickness direction of the coplanar first and second alignment
layers 170 and 260).

[0061]The liquid crystal layer 400 is disposed in a space formed and
bounded by the first and second substrates 100 and 200, and within the
sealants 310 and 320. The liquid crystal layer 400 desirably has a
twisted nematic (TN) mode, which rotates 90° between the first and
second alignment layers 170 and 260. The alignment of the liquid crystal
layer 400 is changed by a voltage difference between the pixel electrodes
160 and the common electrode 250.

[0062]The liquid crystal display 1 can further include a plurality of
spacers (not shown) to maintain a gap between the first and second
substrates 100 and 200. The spacers can have different shapes such as,
for example, a ball spacer or a column spacer.

[0063]It is critical to align the pixel electrodes 160 of the first
substrate 100 and the color filters 230 of the second substrate 200
precisely. When the alignment of the pixel electrodes 160 and the color
filters 230 is imprecise, it is difficult to realize a desired image in
the display. Also, it is critical to align the thin film transistors 140
of the first substrate 100 and the black matrix 220 of the second
substrate 200 precisely. When the alignment of the thin film transistors
140 and the black matrix 220 is imprecise, light from an external can be
emitted to the thin film transistors 140, thereby deteriorating the light
emitting quality of the thin film transistors 140. The method for
manufacturing the liquid crystal display according to an exemplary
embodiment of the present invention will now be described with reference
to FIGS. 3A and 3G as well as FIGS. 1 and 2.

[0064]FIGS. 3A to 3G illustrate a method for manufacturing the liquid
crystal display shown in FIG. 1. As shown in FIG. 3A, sealants 310 and
350 are formed on a first mother substrate 101. Where the first mother
substrate 101 is cut along a cutting line (CUTTING LINE in FIG. 3A), it
becomes the first substrate 100 as shown in FIG. 1. Thus, in FIG. 3, the
single first mother substrate 101 can provide four first substrates 100.

[0065]The first mother substrate 101 is manufactured according to a method
known in the art. Thus, the description of the manufacture of the first
mother substrate 101 will be omitted.

[0066]The sealants 310 and 350 include main sealants 310 and auxiliary
sealants 350. The sealants 310 and 350 are initially uncured.

[0067]Each of the main sealants 310 substantially surrounds the display
region, but not entirely. An injection opening 311 is thus formed in the
main sealant 310 to open a part of the display region. The auxiliary
sealants 350 are formed outside of the cutting line (i.e., outside of the
non-display region as shown in FIG. 1) and is thus scattered across the
first mother substrate 101. The shape of the auxiliary sealants 350 is
not limited to that shown in the exemplary embodiment of the present
embodiment. For example, the auxiliary sealants 350 can vary in shape and
can include an elongated shape.

[0068]The auxiliary sealants 350 can be formed by dispensing a composition
of a sealant on the first mother substrate 101. The composition of the
sealant used to form the auxiliary sealants 350 will be described in
detail.

[0069]The composition of the sealant includes an epoxy resin and a
diazonaphthoquinone type initiator. A molar ratio between the
diazonaphthoquinone type initiator to the epoxy resin can be about 1:10
to about 1:100, respectively. The epoxy resin included in the composition
of the sealant can represent an unpolymerized epoxy monomer. The
composition of the sealant can desirably be afforded in a gel state to
readily form the auxiliary sealants 350.

[0070]In an embodiment, the epoxy resin can be represented by a following
chemical formula 1.

##STR00002##

[0071]Here, R' may include at least one selected from the group consisting
of amide, ester, ether, sulfide, sulfoxide, hydroxide, halide, imide, an
aza group, amine, an azo group, aldehyde, a carboxy group, anhydride,
urea, an alkyl group such as a methyl group, and an alkylaryl.

[0072]More specifically, the epoxy resin can be represented by following
chemical formulas 2 and 3 (where m is 0 or an integer in chemical formula
3).

##STR00003##

[0073]Preferably, the epoxy resin includes at least two epoxy groups,
which can be represented by following chemical formulas 4 and 5.

##STR00004##

[0074]The epoxy resin represented by the chemical formula 5 includes a
novolac type epoxy resin, i.e., a phenol-based novolac epoxy resin (where
R''═H and x is an integer). In addition to, or alternatively, the
epoxy resin can include another novolac type epoxy resin, i.e., a cresol
novolac epoxy resin (where R''═CH3 and x is an integer). It will
be understood that, though homopolymers are exemplified with respect to
chemical formula 5, novolac type epoxy resins that are contemplated for
use as disclosed herein can also include copolymers of
glycidyl-substituted phenols and/or cresols with phenol and/or cresols,
can have free phenolic --OH groups and/or methylol end groups, and can
have branched structures, and therefore representative novolac type epoxy
resins should not be considered as limited thereto.

[0075]The diazonaphthoquinone type initiator includes a photo initiator
such as diazonaphthoquinone or diazonaphthoquinone-novolac resin.

[0076]The diazonaphthoquinone-novolac resin can be represented by chemical
formula 6.

##STR00005##

[0077]The diazonaphthoquinone-novolac resin represented by chemical
formula 6 includes a phenol novolac resin substituted with
diazonaphthoquinone groups. The number-average molecular weight (Mn) of
the phenol novolac resin used in the diazonaphthoquinone-novolac resin
can be from about 1,000 to about 50,000 g/mol. Hereinafter, the
diazonaphthoquinone-novolac resin represented by chemical formula 6 will
be exemplified for purposes of discussion by the diazonaphthoquinone type
initiator substituent groups. The composition of the sealant can further
include a hardener. The molar ratio between the hardener and the epoxy
resin can be about 1:5 to about 1:20, respectively. The hardener can
include a dihydrazide type material. More specifically, the hardener can
include at least one selected from the group consisting of valine
dihydrazide, adipic acid dihydrazide and sebacic acid dihydrazide.

[0078]As shown in FIG. 3B, a second mother substrate 201 is disposed over
and aligned with the first mother substrate to thereby provide a mother
substrate assembling body shown in FIG. 3c. When the second mother
substrate is cut along a cutting line (CUTTING LINE in FIG. 3B), it
becomes the second substrate 200 shown FIG. 1. The second mother
substrate 201 in FIG. 3B can provide four second substrates 200.

[0079]The first and second mother substrates 101 and 201 are aligned so
that the pixel electrodes 160 aligns to the corresponding color filters
230 when viewed perpendicular to the plane of first and second mother
substrates 101 and 201. Further, the thin film transistors 140 of the
first mother substrate 101 and the black matrix 220 of the second mother
substrate 201 are aligned to correspond with each other.

[0080]The second mother substrate 201 can be manufactured by a method
known in the art. Thus, descriptions will be omitted.

[0081]FIG. 3c is a sectional view the mother substrate assembling body 501
taken along the line IIIc-IIIc in FIG. 3A, and illustrates the alignment
of both the first and second mother substrates 101 and 201 to
corresponding with each other, to thereby the mother substrate assembling
body 501.

[0083]Upon exposure to UV radiation, the diazonaphthoquinone groups of the
diazonaphthoquinone-novolac resin rearrange as shown in a reaction
formula 1, to form an indene carboxylic acid ("ICA")-novolac resin. R in
the reaction formula 1 refers to the phenolic novolac resin of the
diazonaphthoquinone-novolac resin represented by chemical formula 6.

##STR00006##

[0084]As shown in reaction formula 2, the epoxy resin reacts with the
indene carboxylic acid-novolac resin to be cured by polymerization and
branching. ICA in the reaction formula 2 refers to ICA-novolac resin. In
this way, the auxiliary sealants 350 are cured. The cured auxiliary
sealants 350' have a high glass transition temperature. Where an epoxy
resin having at least two epoxy groups is used, a high degree of
polymerization and branching can be achieved. Thus, the cured auxiliary
sealant 350' has a higher glass transition temperature when compared with
sealants prepared with acrylic resins or epoxy resins having fewer than
two epoxy groups per reactive molecule.

##STR00007##

[0085]Where a hardener is used, epoxy groups that are not reacted during
the curing process of the epoxy resin react with the hardener to form a
crosslink. As the crosslink is formed, the glass transition temperature
further increases and mechanical strength is further enhanced.

[0086]The mother substrate assembling body 501 is then pressed and heated
in an oven.

[0087]The auxiliary sealants 350 according to the embodiment have a high
mechanical strength when cured. The epoxy resin which is the main
component of the auxiliary sealants 350 has a higher adhesion to a glass
substrate, an insulating layer and an alignment layer, when compared to
the adhesion of an acrylic resin toward these substrates and layers.
Thus, the auxiliary sealants 350 effectively maintain alignment of the
mother substrate assembling body 501 while the mother substrate
assembling body 501 is pressed and moved.

[0088]Then, the mother substrate assembling body 501 is heated in the oven
(HEAT as shown in FIG. 3E) to thereby cure the main sealants 310 to form
cured main sealant 310'. The curing temperature of the main sealants 310
can be from about 100° C. to about 140° C. In this
embodiment, the glass transition temperature of the auxiliary sealants
350 is higher than the curing temperature of the main sealants 310. Thus,
the auxiliary sealants 350 are not deformed until the main sealants 310
are completely cured, and effectively maintain the alignment of the
mother substrate assembling body 501.

[0089]FIG. 3F shows the result of two mother substrates 101 and 201 after
being cut along a cutting line (CUTTING LINE in FIGS. 3A and 3B) to make
four substrate assemblies 502. Each substrate assembly 502 includes the
first substrate 100, the second substrate 200, and the cured main sealant
310' disposed between the first and second substrates 100 and 200. That
is, the substrate assembly 502 does not include the auxiliary sealants
350. The two substrates 100 and 200 remain a state aligned by the cured
main sealant 310'.

[0090]As shown in FIG. 3G, liquid crystals 20 are injected between the two
substrates 100 and 200 through the injection opening 311 formed in the
cured main sealant 310' to thereby form the liquid crystal layer 400. The
liquid crystal is injected according to the following filling method.

[0091]The pressure within the space between the both substrates 100 and
200 is reduced in a vacuum chamber (not shown), and the injection opening
311 is contacted to the liquid crystals 20 contained in a liquid crystal
accommodator 10. Then, the liquid crystals 20 are injected into the space
between the two substrates 100 and 200 through the injection opening 311
by capillary action and pressure difference to thereby form the liquid
crystal layer 400. After the liquid crystals 20 are injected, an inert
gas is supplied to the chamber to raise the ambient pressure within the
chamber. Then, the injection opening 311 is separated from the liquid
crystal accommodator 10.

[0092]The injection opening 311 is then capped by the capping sealant 320
and the capping sealant 320 is cured, thereby completing the liquid
crystal display 1 as shown in FIGS. 1 and 2.

[0093]According to the exemplary embodiment, the auxiliary sealants 350
have, when cured, high strength, high glass transition temperature, and
good adhesion property to the mother substrates 101 and 201. Thus, the
auxiliary sealants 350 effectively maintain precise alignment of the two
mother substrates 101 and 201 while the mother substrate assembling body
501 is pressed and moved, and while the main sealant 310 is cured.

[0094]The effect of the auxiliary sealants 350 disclosed herein is further
demonstrated according to the exemplary embodiment. The example used a
phenol novolac epoxy resin as an epoxy resin, a
diazonaphthoquinone-novolac resin as a photo initiator and valine
dihydrazide as a hardener to form the auxiliary sealants 350. The molar
ratio between the photo initiator, the hardener and the epoxy resin was
about 1:2:20.

[0095]The glass transition temperature of the auxiliary sealants 350, as
determined by a thermal mechanical analyzer ("TMA") was about
148.9° C., and the main sealants 310 were cured at approximately
about 140° C.

[0096]The alignment error (as measured by the deviation of color filter
(of the second substrate) relative to the pixel electrode (of the first
substrate), aligned along the x-axis of the plane) for an auxiliary
sealants 350 including an acrylic resin as a primary compositional
material, ranged from about -3 μm to about 3 μm. However, for an
epoxy novolac type sealants used as the auxiliary sealants as disclosed
herein, the alignment error ranged from about -1 μm to about 2 μm,
thus exhibiting an unexpectedly significant and dramatic improvement in
the alignment error.

[0097]Next, a liquid crystal display according to another exemplary
embodiment of the present invention with reference to FIG. 4.

[0098]FIG. 4 is an exploded perspective view of a liquid crystal display
according to another exemplary embodiment of the present invention.

[0099]A structure of a liquid crystal display 2 according to the
embodiment is similar to that of the liquid crystal display 1 as shown in
FIG. 1. As compared with FIG. 1, the elements performing the same
operations are indicates as the same reference numerals, and the detailed
description thereof is omitted.

[0100]That is, the liquid crystal display 2 according to the embodiment
includes a first substrate 100, on which a plurality of gate lines 121
and a plurality of gate pads 122 connected with the gate lines 121, and a
plurality of data lines 131 and a plurality of data pads 132 connected
with the data lines 131, a sealant 310a disposed between the first and
second substrate 100 and 200. In addition, the first substrate 100
includes a plurality of auxiliary sealants 350 scattered thereon like in
FIG. 1.

[0101]However, unlike FIG. 1, a capping sealant is not provided in the
liquid crystal display device 2. The main sealant 310a thus entirely
surrounds the display region (DISPLAY REGION in FIG. 4) without an
opening.

[0102]Referring FIGS. 5A and 5B, a method for manufacturing the liquid
crystal display in FIG. 4 will be described.

[0104]As shown in FIG. 5A, main sealants 310a are formed on a first mother
substrate 101 surrounding display regions without an opening,
respectively.

[0105]Referring FIG. 5B, liquid crystals 20 are deposited by dropping in a
space 400 surrounded by each main sealant 310 to form a liquid crystal
layer (not shown). The liquid crystal layer may be not limited to a TN
mode liquid crystal layer. Alternatively, the liquid crystal layer can
vary and can include liquid crystals having a vertical alignment (VA)
mode.

[0106]Next, though not shown, a second mother substrate is disposed on the
main sealants 310 on the first mother substrate 101 and is aligned, the
auxiliary sealants 350 is UV cured, and the main sealants 310 are heat
cured and then cut along the cutting line to provide a liquid crystal
display 2.

[0107]Thus, according to this embodiment, the auxiliary sealants 350
exhibit high strength, high glass transition temperature and good
adhesion property to the two mother substrates for the first and second
substrates, respectively, when cured, thereby effectively maintaining the
alignment of the two mother substrates.

[0108]As described above, a method for manufacturing a display device
having two substrates that are precisely aligned is provided.

[0109]Also, a composition of a sealant used for making a display device
having two substrates aligned more precisely is also disclosed.

[0110]Although exemplary embodiments of the present invention have been
shown and described, it will be appreciated by those skilled in the art
that changes can be made without departing from the principles and spirit
of the invention, the scope of which is defined in the appended claims
and their equivalents.